The tonometer is an ophthalmologic apparatus used for detecting glaucoma. Glaucoma is a disease of the eye marked by increased pressure within the eyeball that can result in damage to the optic disk causing gradual loss of vision. Essentially, the tonometer is an instrument used to measure the tension of an eyeball. More particularly the tonometer accurately measures the intraocular pressure of the eyeball through the eye wall.
The tonometer functions such that the lens of a tonometer is positioned to contact an eyeball with a predetermined pressure. The eyeball is instantaneously deformed and the resistance of the eyeball to deformation is detected and measured as the intraocular pressure. There are two principal types of tonometers used in the ophthalmologic field at the present time, one being the pneumotonometer and the other being an applanation tonometer. The pneumotonometer detects eye pressure by means of a blast of air. Thus, the pneumotonometer does not require optics for viewing the deformed eyeball for the measurement of intraocular pressure. In contrast to the pneumotonometer, the applanation tonometer measures the intraocular pressure through measurement of the deformed surface area of the eyeball using optics. Although both of these tonometers use different methods to measure intraocular pressure, both still require its respective lens to come in contact with the eyeball of a patient.
Contact tonometers raise serious concerns regarding the spread of contagious disease. The possible spread of conjunctivitis, adenovirus, herpes simplex, and hepatitis between patients which come in contact with a common tonometer is of major concern. Additionally, the emergence of the epidemic AIDS only heightens this concern. Current methods for cleaning the tonometer lens tip include soaking the removable tip in cleansing chemical agents. Such chemical agents may include diluted bleach, hydrogen peroxide and isopropyl alcohol. Disadvantages with the use of these cleansing agents include incomplete tip disinfection, corneal contact with cleaning solutions, tonometer tip damage or loss, and the time and expense required for such cleansing.
One attempt to overcome the above mentioned disadvantages, is the Tonometer Probe Cap, manufactured by U.S. Optical Specialties, located in South Bend, Ind., and BioRad, Inc., located in Santa Ana, Calif. The Tonometer Probe Cap is designed to be used on the pneumotonometer. The tonometer probe cap is entirely constructed of latex. In use, the disposable Tonometer Probe Cap is placed over the tip of the pneumotonometer and provides a sterile environment devoid of contagious disease. Hence, every time the tip of the pneumotonometer is to contact a different patient, the attending physician places a new sterile latex probe cap over the tip of the pneumotonometer to ensure a sterile environment. However, the employment of the latex tonometer probe cap on the pneumotonometer may decrease the accuracy for the measurement of intraocular pressure of the eyeball. Additionally, the modern trend is to move away from the pneumotonometer for measuring intraocular pressure, as a blast of air on the eyeball is no longer looked favorable upon. Moreover, the latex tonometer probe cap is not applicable for usage on tonometers such as the applanation tonometer. The latter situation arises because tonometers such as the applanation tonometer measure the intraocular pressure through optics and, as mentioned above, the latex tonometer probe cap is designed to be employed on a nonoptical tonometer.
Accordingly, it is an object of the subject invention to provide a disposable sterile protective lens cover for an applanation tonometer.
Another object of the invention is to provide a protective lens cover for an applanation tonometer which greatly reduces the risk of the spread of contagious disease.
Still a further object of the subject invention is to provide a protective lens cover for a tonometer which enhances the optical qualities of the tonometer.
An additional object of the subject invention is to provide a protective lens cover which is packaged in a sterilized environment.
Yet another object of the subject invention is to provide a protective lens cover which is disposable after each patients usage.
It is another object of the subject invention to provide a protective lens cover that may be readily manufactured by a conventional molding process in quantities at a unit cost of pennies.